Nosocomial infections (NIs) are infections acquired by patients during hospitalization. An estimated 5% to 10% of human patients admitted to hospitals develop an NI.1 Among identified pathogens in human intensive care units (ICUs), 70% are resistant to at least one antimicrobial.2 In 2008, 64% of biosecurity experts at veterinary teaching hospitals believed that the risk of NI among their patients had increased in the preceding 10 years.3 Between 2003 and 2008, 82% of veterinary teaching hospitals reported outbreaks of NIs and 45% reported more than one NI outbreak.3 In human medicine, urinary tract infections (UTIs), pneumonia, surgical site infections (SSIs), and bloodstream infections (BSIs) account for approximately 80% of all NIs.4 This article reviews the most common NIs, the human and veterinary literature for each type of infection, and the diagnostic and treatment protocols as well as prevention strategies.